TO MAKE THE GRAHAM CRACKER CRUST: Preheat the oven to 350℉ and lower your oven rack to the third level from the bottom. If using a pre-made graham cracker crust, skip ahead to step 7.
Lightly spray a 9" or 10" pie plate with cooking spray.
In the bowl of a food processor, add the graham crackers, sugar, and salt, and pulse until the crackers are almost completely ground.
Add the melted butter to the food processor and pulse until the cracker crumbs are ground fine and the mixture is evenly moistened and clumping.
Pour the crumbs into the pie plate and press into a compact and even layer. Use the bottom of a flat glass to help tamp down the crust. Press the graham crackers up the side of the pie plate as well, packing the crumbs together as tightly and evenly as possible.
Pop the pie plate in the freezer for 15-20 minutes until firm.
While the crust is in the freezer, beat one whole egg in a small dish.
Once firm, remove the crust from the freezer or grab your premade crust.
Using a pastry brush, lightly brush the inside bottom and sides of the pie crust with the egg wash. You might not use all the egg wash. Just make sure there's an even layer of egg coating the inside of the crust, but not saturating it.
Bake a homemade graham cracker crust in a 350℉ oven for 12-15 minutes and bake a store bought crust at 350℉ for 10-12 minutes. You want the crust just beginning to turn brown and the egg wash baked on.
To make the pumpkin pie filling: In a medium sized bowl, combine all the pie filling ingredients and whisk until smooth and well incorporated.
Set the pie plate onto a sheet pan, and pour the pumpkin filling onto the hot graham cracker crust. Pop the pie plate (now on a sheet pan) back into the oven.
Bake at 350℉ for 55-65 minutes, until the pie is puffed and jiggly, but not liquid. If you have an instant read thermometer, the internal temp should read 175º.
Once the pie is done, turn the oven off and crack open the oven door. Leave the pie inside to cool for about 1 hour. After one hour, allow the pie to cool to room temperature and then transfer to the fridge to set for 6 hours or preferably overnight.